/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.log;

import org.apache.commons.logging.Log;
import org.springframework.lang.Nullable;

import java.util.function.Function;

/**
 * Utility methods for formatting and logging messages.
 *
 * <p>Mainly for internal use within the framework with Apache Commons Logging,
 * typically in the form of the {@code spring-jcl} bridge but also compatible
 * with other Commons Logging bridges.
 *
 * @author Rossen Stoyanchev
 * @author Juergen Hoeller
 * @since 5.1
 */
public abstract class LogFormatUtils {

    /**
     * Format the given value via {@code toString()}, quoting it if it is a
     * {@link CharSequence}, and possibly truncating at 100 if limitLength is
     * set to true.
     *
     * @param value       the value to format
     * @param limitLength whether to truncate large formatted values (over 100)
     * @return the formatted value
     */
    public static String formatValue(@Nullable Object value, boolean limitLength) {
        if (value == null) {
            return "";
        }
        String str;
        if (value instanceof CharSequence) {
            str = "\"" + value + "\"";
        }
        else {
            try {
                str = value.toString();
            }
            catch (Throwable ex) {
                str = ex.toString();
            }
        }
        return (limitLength && str.length() > 100 ? str.substring(0, 100) + " (truncated)..." : str);
    }

    /**
     * Use this to log a message with different levels of detail (or different
     * messages) at TRACE vs DEBUG log levels. Effectively, a substitute for:
     * <pre class="code">
     * if (logger.isDebugEnabled()) {
     *   String str = logger.isTraceEnabled() ? "..." : "...";
     *   if (logger.isTraceEnabled()) {
     *     logger.trace(str);
     *   }
     *   else {
     *     logger.debug(str);
     *   }
     * }
     * </pre>
     *
     * @param logger         the logger to use to log the message
     * @param messageFactory function that accepts a boolean set to the value
     *                       of {@link Log#isTraceEnabled()}
     */
    public static void traceDebug(Log logger, Function<Boolean, String> messageFactory) {
        if (logger.isDebugEnabled()) {
            boolean traceEnabled = logger.isTraceEnabled();
            String logMessage = messageFactory.apply(traceEnabled);
            if (traceEnabled) {
                logger.trace(logMessage);
            }
            else {
                logger.debug(logMessage);
            }
        }
    }

}
